Application is made by a group of vision researchers to obtain support for the acquisition of a state-of-the-art energy dispersive x-ray microanalytical and image processing system. The system would be used to update a scanning electron microscope already used on a shared basis in the Department of Ophthalmology. This new instrumentation is needed to enable members of the group to do quantitative microanalysis of alterations in extracellular and intracellular electrolytes in ocular tissues (e.g., during preservation of corneal tissue for transplantation, in pathological conditions and following treatment with various drugs). Image processing capabilities are needed to allow for precise quantitation (e.g., of the rate of corneal neovascularization under various conditions, the rate of corneal wound healing in normal and diabetic animals treated with various drugs and compounds, and the size and shape of regenerated ocular cells). The availability of this new instrumentation will facilitate research efforts leading to a better understanding of the mechanisms involved in sight-threatening pathological conditions.